This invention relates generally to control systems, and more particularly to control systems for garage door openers and their method of operation.
Various types of automatic garage door openers have existed for many years. Conventional automatic garage door openers are electromechanical devices which raise and lower a garage door in response to actuating signals. The actuating signals are often electrical signals transmitted by actuation of a push-button switch through electrical wires or by radio frequency from a battery-operated, remote controller. In either case the electrical signals initiate movement of the garage door from the opposite condition in which it resides. That is, if the garage door is open, the actuating signal closes it. Alternatively, when the garage door is closed, the actuating signal will open the garage door.
In addition, typical garage door openers often include a halt cycle wherein the garage door drive motor is de-energized if an actuating signal is generated during opening or closing of the door. Conventionally a garage door may continue to travel or “coast” for some distance when the power is removed from the drive motor. This problem is particularly prevalent when a stop signal is received when the garage door is traveling in the downward direction where lower dynamic friction forces may not be sufficient to overcome the inertia of the moving garage door.
Prior attempts to remedy this problem have included adding friction to the garage door components to slow the coasting motion. However, the additional friction forces can be difficult to control and implement.